Humminbird LCR W, Руководство пользователя

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return, in varying densities of pixelization. This bottom depiction is useful in locating structure, by
comparing relative density as well as depth.
The transmitted sonar signal travels downward, and is reflected back toward the surface
by the bottom or other objects for display on-screen. The signal does not stop there - it is
reflected downward again by the surface of the water, and a weak "second return" is usually
visible if the depth range is sufficient to see it. A second return is shown in the figure below. Some
users use this second return as an indicator when setting the sensitivity bias.
If a target is detected between the surface and the bottom, it is displayed as a fish symbol.
Depending on the strength of the signal reflected from the object, one of three different size
symbols is used. These reflected signals are "normalized" for depth, so that a small fish does not
appear to be a large fish if it is close the boat.
Since some species of fish tend to be better reflectors of sonar than others, the strength of return
is not always an accurate indicator of fish size, however, typically the larger the fish, the larger the
signal return.